This invention relates to an ink cartridge for supplying ink to a head of a record apparatus and a method of ink injection thereinto.
An ink jet record apparatus generally comprises a record head mounted on a carriage and moving in the width direction of record paper, and paper feed means for moving the record paper relatively in a direction orthogonal to the move direction of the record head.
Such an ink jet record apparatus prints on record paper by ejecting ink droplets from a record head based on print data.
A record head capable of ejecting black ink, yellow ink, cyan ink, and magenta ink, for example, is mounted on a carriage and in addition to text print in black ink, full-color print is made possible by changing the ink ejection percentage.
Thus, ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink to the record head are placed in the main unit of the apparatus.
In the ordinary ink jet record apparatus, the ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink are mounted on a carriage and are moved together with the carriage.
In the recent record apparatus, the carriage has been moved at high speed for the purpose of increasing the record speed.
In such a record apparatus, pressure fluctuation occurs in internal ink as an ink supply tube is extended and bent with acceleration and deceleration of the carriage, making unstable ejecting of ink droplets from the record head.
Thus, such an ink cartridge is proposed, that comprises a lower ink storage chamber (ink tank chamber) opened to the atmosphere side, an upper ink storage chamber (ink end chamber) for head connection, connected via an ink flow passage to the lower ink storage chamber, and a differential pressure regulating valve placed at midpoint in a passage connecting the upper ink storage chamber and a head supply port.
According to the ink cartridge, a negative pressure is generated on the head side by negative pressure generation means and the differential pressure regulating valve is opened accordingly for supplying ink to the record head, so that the adverse effect on ink produced by pressure fluctuation mentioned above is lessened and ink can be supplied to the record head at the optimum water head difference.
In the ink cartridge, an opening portion for ink injection is constructed by a single opening, and thus ink cannot be injected under ink injection conditions respectively required for the ink tank chamber and the ink end chamber.
That is, the ink end chamber must contain no atmosphere and have a proper ink amount. On the other hand, the ink tank chamber must have a proper ink amount.
Therefore, ink needs to be injected into the separate chambers under different conditions.
Particularly, if ink is injected into the ink end chamber in the cartridge under the ink injection (atmosphere injection) conditions required for the ink tank chamber, air is mixed into not only the ink tank chamber, but also the ink end chamber. Consequently, bubbles are mixed into ink supplied to the head when ink is used, and stability on printing cannot be ensured; this is a problem.
It is therefore an object of the invention to provide an ink cartridge and a method of ink injection into the ink cartridge, for making it possible to prevent bubbles from being mixed into ink supplied to a head when ink is used, and ensure stability on printing.